U.S. patent application number 12/626078 was filed with the patent office on 2011-05-26 for electronic device with fuse structure and method for repairing the same.
Invention is credited to Jia-Fu Jhang, Cheng-Feng Peng, Ming-Sheng Yang.
Application Number | 20110121426 12/626078 |
Document ID | / |
Family ID | 44033021 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110121426 |
Kind Code |
A1 |
Yang; Ming-Sheng ; et
al. |
May 26, 2011 |
ELECTRONIC DEVICE WITH FUSE STRUCTURE AND METHOD FOR REPAIRING THE
SAME
Abstract
According to an embodiment of the invention, an electronic
device with a fuse structure is provided. The electronic device
includes a substrate, at least a conducting layer formed in or on
the substrate and having a fuse area, and at least a lens disposed
overlying the fuse area of the conducting layer, wherein the lens
is substantially aligned with the fuse area and there is no optical
device disposed between the lens and the fuse area.
Inventors: |
Yang; Ming-Sheng; (Hsinchu
City, TW) ; Peng; Cheng-Feng; (Hsinchu County,
TW) ; Jhang; Jia-Fu; (Miaoli County, TW) |
Family ID: |
44033021 |
Appl. No.: |
12/626078 |
Filed: |
November 25, 2009 |
Current U.S.
Class: |
257/529 ;
257/E21.592; 257/E23.149; 438/4 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/0002 20130101; H01L 2924/00 20130101; H01L 2924/12044
20130101; H01L 23/5258 20130101 |
Class at
Publication: |
257/529 ; 438/4;
257/E23.149; 257/E21.592 |
International
Class: |
H01L 23/525 20060101
H01L023/525; H01L 21/768 20060101 H01L021/768 |
Claims
1. An electronic device with a fuse structure, comprising: a
substrate; at least a conducting layer formed in or on the
substrate and having a fuse area; and at least a lens disposed
overlying the fuse area of the conducting layer, wherein the lens
is substantially aligned with the fuse area and there is no optical
device disposed between the lens and the fuse area.
2. The electronic device with a fuse structure as claimed in claim
1, further comprising a passivation layer formed between the lens
and the conducting layer.
3. The electronic device with a fuse structure as claimed in claim
1, further comprising an opening formed in the fuse area.
4. The electronic device with a fuse structure as claimed in claim
3, wherein the opening separates the conducting layer into a first
portion and a second portion electrically insulated from the first
portion.
5. The electronic device with a fuse structure as claimed in claim
3, wherein the lens overlying the opening is at least partially
broken.
6. The electronic device with a fuse structure as claimed in claim
1, wherein the lens comprises a microlens.
7. The electronic device with a fuse structure as claimed in claim
1, wherein the lens directly contacts with the fuse area of the
conducting layer.
8. The electronic device with a fuse structure as claimed in claim
1, wherein the electronic device comprises a RAM device.
9. An electronic device with a fuse structure, comprising: a
substrate; a plurality of conducting layers formed in or on the
substrate and each having a fuse area; and a plurality of lenses
each disposed overlying one of the fuse areas of the conducting
layers, wherein each of the lenses is substantially aligned with
the respective fuse area and there is no optical device disposed
between each of the lenses and the respective fuse area.
10. The electronic device with a fuse structure as claimed in claim
9, further comprising at least an opening formed in at least one of
the fuse areas.
11. The electronic device with a fuse structure as claimed in claim
10, wherein the opening separates the respective conducting layer
into a first portion and a second portion electrically insulated
from the first portion.
12. The electronic device with a fuse structure as claimed in claim
10, wherein the lens overlying the opening is at least partially
broken.
13. A method for repairing an electronic device with a fuse
structure, comprising: providing an electronic device comprising: a
substrate; a plurality of conducting layers formed in or on the
substrate and each having a fuse area; and a plurality of lenses
each disposed overlying one of the fuse areas of the conducting
layers, wherein each of the lenses is substantially aligned with
the respective fuse area and there is no optical device disposed
between each of the lenses and the respective fuse area; and
irradiating one of the lenses by a light beam to remove at least a
portion of the respective fuse area of the conducting layer under
the respective lens.
14. The method for repairing an electronic device with a fuse
structure as claimed in claim 13, wherein the light beam comprises
a laser light beam.
15. The method for repairing an electronic device with a fuse
structure as claimed in claim 13, wherein after the portion of the
respective fuse area is removed by the light beam, the respective
conducting layer is separated into a first portion and a second
portion electrically insulated from the first portion.
16. The method for repairing an electronic device with a fuse
structure as claimed in claim 13, wherein after the portion of the
respective fuse area is removed by the light beam, the respective
lens is partially or completely removed.
17. The method for repairing an electronic device with a fuse
structure as claimed in claim 13, further comprising a test process
of the electronic device to determine which one of the lenses is
irradiated by the light beam.
18. The method for repairing an electronic device with a fuse
structure as claimed in claim 13, wherein the lenses comprise a
microlens.
19. The method for repairing an electronic device with a fuse
structure as claimed in claim 13, wherein the electronic device
comprises a RAM device.
20. The method for repairing an electronic device with a fuse
structure as claimed in claim 12, further comprising removing the
lens overlying the conducting layers.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electronic device with a
fuse structure, and in particular relates to a method for repairing
an electronic device with a fuse structure.
[0003] 2. Description of the Related Art
[0004] Advances in semiconductor processing technologies are
dramatically reducing the feature sizes of integrated circuit (IC)
devices while increasing device packing density. Unfortunately, as
the density of the IC devices increases and the number of discrete
devices increases on the IC, fabrication yield for many IC devices
(chip yield) decrease. For example, one IC device, wherein an
increase in the number of discrete devices decreases fabrication
yields, is the dynamic random access memory (DRAM).
[0005] One method used to hinder decrease in fabrication yield for
RAM devices due to increase in discrete devices thereof, is to
provide additional rows of memory cells and fuse each row by fuse
structures. Currently laser light beams are used to open
connections (breaking the fuse structures) in the RAM devices, such
as in DRAM or SRAM devices, to disable defective rows of memory
cells and to modify the address decoder so that spare rows of
memory cells are selected instead.
[0006] Meanwhile, IC devices that have high packing density cannot,
in general, be repaired or modified. There exists, however, a large
class of ICs that are intended to be repairable and/or modifiable.
In certain cases, no real circuit exits until the ICs has been
personalized by breaking certain connections, thereby determining
how the components are to be connected to one another. In this
case, fuse structures may be formed between components. The fuse
structures may be optionally removed by a laser light beam to
repair and/or modify the IC devices.
[0007] However, using precise laser beams to repair and/or modify
the IC devices increases fabrication costs due to special machinery
and high power required for the laser beam process. In some cases,
if the power of the laser light beam is too high, other components
other than the fuse structures intended to be broken may also be
broken. In addition, designing of large fuse structure layouts can
occupy much chip area. Moreover, despite the special machinery,
fabrication yield still decreases due to the high precision
process.
[0008] Thus, an electronic device with a new fuse structure is
desired to facilitate the laser repairing process.
BRIEF SUMMARY OF THE INVENTION
[0009] According to an illustrative embodiment, an electronic
device with a fuse structure is provided. The electronic device
with a fuse structure includes a substrate, at least a conducting
layer formed in or on the substrate and having a fuse area, and at
least a lens disposed overlying the fuse area of the conducting
layer, wherein the lens is substantially aligned with the fuse area
and there is no optical device disposed between the lens and the
fuse area.
[0010] According to an illustrative embodiment, an electronic
device with a fuse structure is provided. The electronic device
with a fuse structure includes a substrate, a plurality of
conducting layers formed in or on the substrate and each having a
fuse area, and a plurality lenses each disposed overlying one of
the fuse areas of the conducting layers, wherein each of the lenses
is substantially aligned with the respective fuse area and there is
no optical device disposed between each of the lenses and the
respective fuse area.
[0011] According to an illustrative embodiment, a method for
repairing an electronic device with a fuse structure is provided.
The method includes providing an electronic device including a
substrate, a plurality of conducting layers formed in or on the
substrate and each having a fuse area, and a plurality lenses each
disposed overlying one of the fuse areas of the conducting layers,
wherein each of the lenses is substantially aligned with the
respective fuse area and there is no optical device disposed
between each of the lenses and the respective fuse area. The method
further includes irradiating one of the lenses by a light beam to
remove at least a portion of the respective fuse area of the
conducting layer under the respective lens.
[0012] A detailed description is given in the following embodiments
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention can be more fully understood by
reading the subsequent detailed description and examples with
references made to the accompanying drawings, wherein:
[0014] FIGS. 1A and 1B are a cross-sectional view and a top view of
an electronic device with a fuse structure known by the inventors,
respectively;
[0015] FIGS. 2A and 2B respectively show a cross-sectional view and
a top view of an electronic device with a fuse structure according
to an embodiment of the present invention;
[0016] FIG. 2C is an enlarged cross-sectional view of the
electronic device shown in FIG. 2A;
[0017] FIGS. 3A and 3B respectively shows cross-sectional views of
an electronic device with a fuse structure according to an
embodiment of the present invention;
[0018] FIG. 3C is a top view of the electronic device shown in FIG.
3A or 3B;
[0019] FIGS. 4A and 4B are a cross-sectional view and a top view of
an electronic device with a fuse structure according to an
embodiment of the present invention; and
[0020] FIG. 5 is a cross-sectional view of an electronic device
with a fuse structure according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The following description is of the best-contemplated mode
of carrying out the invention. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in a limiting sense. The scope of the invention
is best determined by reference to the appended claims.
[0022] It is understood, that the following disclosure provides
many difference embodiments, or examples, for implementing
different features of the invention. Specific examples of
components and arrangements are described below to simplify the
present disclosure. These are, of course, merely examples and are
not intended to be limiting. In addition, the present disclosure
may repeat reference numbers and/or letters in the various
examples. This repetition is for the purpose of simplicity and
clarity and does not in itself dictate a relationship between the
various embodiments and/or configurations discussed. Furthermore,
descriptions of a first layer "on," "overlying," (and like
descriptions) a second layer include embodiments where the first
and second layers are in direct contact and those where one or more
layers are interposing the first and second layers.
[0023] FIGS. 1A-1B demonstrate a cross-sectional view and a top
view of an electronic device with a fuse structure known by the
inventors, respectively, which show a problem with the electronic
device with a fuse structure found by the inventor. As shown in
FIG. 1A, an electronic device with a fuse structure is provided.
The electronic device includes a plurality of conducting layers 102
formed between a substrate 100 and a passivation layer 104. Each of
the conducting layers 102 has a fuse area, which may be irradiated
by a laser light beam to be removed if needed. As shown in FIGS. 1A
and 1B, three different fuse areas 102a, 102b, and 102c of three
different conducting layers 102 which may be electrically insulated
from each other are shown. Each of the fuse areas may be
electrically connected to a specific component. When the integrated
circuit of the electronic device requires modification or repair, a
specific fuse area is removed or broken to open the electrical path
between the specific fuse area and the specific component. For
example, laser light beams may be used to open connections
(breaking the fuse structures) in the RAMs, such as in DRAM or SRAM
devices, to disable defective rows of memory cells and to modify
the address decoder so that spare rows of memory cells are selected
instead. However, due to the laser light beam having some degree of
precision error and the spot size of the laser light beam, the
distance d1 between two nearby fuse areas, such as the fuse areas
102a and 102b, must be about 4 .mu.m to about 8 .mu.m, to ensure
that the laser light beam only cuts the desired fuse area. Thus,
the conducting layers 102 including the fuse areas occupy a large
chip area, hindering size reduction of the electronic device.
[0024] FIGS. 2A-2B respectively show a cross-sectional view and a
top view of an electronic device with a fuse structure according to
an embodiment of the present invention. FIG. 2C shows an enlarged
cross-sectional view of the electronic device shown in FIG. 2A. As
shown in FIGS. 2A and 2B, an electronic device with a fuse
structure in accordance with an embodiment of the invention is
provided. The electronic device includes a substrate 200. The
substrate 200 may include, but is not limited to, a semiconductor
substrate or an insulating substrate. In some cases, the substrate
200 may also include a plurality of semiconductor devices formed
therein. For example, the substrate 200 may include, but is not
limited to, a RAM device such as static random-access-memory
(SRAM), dynamic random-access-memory (DRAM), magnetic
random-access-memory (MRAM), non-volatile-memory (NVM), and/or
combinations thereof. The NVM may further include programmable
read-only-memory (PROM), phase-change-memory, and flash memory. The
plurality of semiconductor devices may further include, but are not
limited to, passive components such as resistors, capacitors, and
inductors, active components such as metal-oxide-semiconductor
field effect transistors (MOSFETs), bipolar transistors, high
voltage transistors, high frequency transistors, or combinations
thereof. The plurality of semiconductor devices may be isolated
from each other by isolation features based on structures
incorporating junction isolation, field isolation, and dielectric
isolation such as local oxidation of silicon (LOCOS) and shallow
trench isolation (STI). In another embodiment, the electronic
device may include an LCD device or any other integrated
circuit.
[0025] In the embodiment shown in FIGS. 2A and 2B, the electronic
device includes at least a conducting layer 202 formed in or on the
substrate 200. In this embodiment, a plurality of conducting layers
202 are formed on the substrate 200. The conducting layer 202 may
include any kind of conducting material, such as a metal material,
a semiconductor material, a conducting polymer material, a
conducting oxide material, or combinations thereof. The conducting
layer 202 is electrically connected to a specific component formed
on and/or in the substrate 200. Each of the conducting layers 202
has a fuse area, such as the fuse areas 202a, 202b, 202c, 202d, and
202e shown in FIGS. 2A and 2B. When the circuit of the electronic
device is needed to be modified or repaired, a specific fuse area
is removed or broken to open the electrical path between the
specific fuse area and the specific component.
[0026] As shown in FIG. 2A, at least a lens 206 is disposed
overlying the fuse area of the conducting layer 202, wherein the
lens 206 is substantially aligned with the fuse area and there is
no optical device disposed between the lens 206 and the fuse area.
In one embodiment, the lens 206 may include a microlens. The
material of the lens 206 may include a transparent material, such
as a transparent oxide, transparent polymer, or the like. The lens
206 may have a lens size ranging from about (but is not limited to)
1 .mu.m to 10 .mu.m, a lens height ranging from about (but is not
limited to) 1 .mu.m to 5 .mu.m, an n value (refractive index)
ranging from about 1 to 2, and a focus length ranging from about 1
.mu.m to 10 .mu.m. The optical device mentioned above may include,
but is not limited to, an image sensor, a light emitting element,
or the like. In the embodiment shown in FIG. 2A, there are a
plurality of lenses 206 disposed overlying the substrate 200. Each
of the lenses 206 is disposed on one of the fuse area of the
conducting layers 202. Each of the lenses 206 is substantially
aligned with a respective fuse area and there is no optical device
disposed between each of the lenses 206 and the respective fuse
area. A passivation layer 204 may be optionally formed between the
lens 206 and the fuse area of the conducting layer 202. The
passivation layer 204 may include, but is not limited to, an oxide,
nitride, or combinations thereof. The lens 206 is used to focus a
light beam such as a laser light beam onto a specific fuse area of
the conducting layer 202 according to requirement. Thus, it is
preferable that the passivation layer 206 between the lens 206 and
the fuse area absorbs minimal laser light. Therefore, the material
of the passivation layer 206 may be chosen accordingly.
[0027] As shown in FIG. 2C, when a specific fuse area of the
conducting layer 202 is determined to be opened, a light beam 208
is directed to irradiate the specific lens 206 overlying the
specific fuse area. For example, a test process of the electronic
device may be optionally performed to determine which one of the
lenses 206 and the fuse area of the conducting layer 202 thereunder
are to be irradiated by the light beam 208. The lens 206 is
designed to focus the light beam 208 onto the fuse area thereunder
to remove at least a portion of the fuse area of the conducting
layer 202. Thus, the energy of the light beam 208 needs to be
strong enough to remove the fuse area of the conducting layer 202.
Depending on different materials of the conducting layer 202,
different light beam 208 sources may be adopted. In one embodiment,
a laser light beam may be used as the light beam 208 to remove at
least a portion of the fuse area of the conducting layer 202, thus
modifying and/or repairing the circuit of the electronic device.
For example, the laser light beam may have a laser energy ranging
between 0.8 and 1.2 microjoules with a spot diameter of 5 microns
and a pulse width of 35 ns. It should be appreciated, however, that
the light source of the light beam 208 is not limited to laser
light beams. In another embodiment, other light sources such as an
ultraviolet light, x-ray light, or other suitable lights may be
used, depending on requirement.
[0028] Because the light beam 208 is "focused" by the lens 206, the
spot size of the light beam 208 can be significantly reduced. In
this case, the distance d2 between nearby fuse areas of the
conducting layers 202 may be also reduced, as shown in FIGS. 2A and
2B. For example, a distance d2 smaller than the distance d1 shown
in FIG. 1 is satisfactory enough to ensure that the light beam 208
will only cut the desired fuse area. Thus, the conducting layers
102 including the fuse areas can occupy less chip area, as compared
with that shown in FIG. 1, facilitating reduction in size of the
electronic device. The precision of light beam 208 irradiation may
also be improved since the lens 206 which may have a bigger size is
now the "target" of the light beam 208. In addition, because the
energy of the light beam 208 will also be focused onto the fuse
area requiring removal, the cutting process of the fuse area may be
performed at a faster speed, leading to higher fabrication yields.
Since the energy of the light beam 208 is enhanced by focusing of
the lens 206, a low-powered light beam 208 source will be
satisfactory enough to modify and/or repair the circuits of the
electronic device. Additionally, expensive machinery is not
required.
[0029] FIGS. 3A and 3B respectively shows cross-sectional views of
an electronic device with a fuse structure according to an
embodiment of the present invention. FIG. 3C shows a top view of
the electronic device shown in FIG. 3A or 3B. In the embodiments
shown in FIG. 3, one of the fuse areas of the conducting layers is
opened (partially removed) to modify and/or repair the circuit of
the electronic device. Referring to FIGS. 3A and 3C, three
conducting layers 302 are formed between an optionally formed
passivation layer 304 and a substrate 300. The conducting layers
302 each has fuse areas 302a, 302b, and 302c, respectively. A
plurality of lenses 306 are disposed overlying the substrate 300.
Each of the lenses 306, such as the lens 306a or 306c, is disposed
overlying a respective fuse area of the conducting layer 302. Each
of the lenses 306 is substantially aligned with a respective fuse
area and there is no optical device disposed therebetween.
[0030] In one embodiment, it is determined that the conducting
layer 302 having the fuse area 302b is to be opened to modify
and/or repair the circuit of the electronic device. A light beam is
directed to irradiate the lens on the fuse area 302b. Then, at
least a portion of the fuse area 302b is removed. As shown in FIG.
3C, after a portion of the fuse area 302b is removed by the light
beam, an opening 310 is formed in the fuse area 302b. In one
embodiment, the opening 310 separates the conducting layer 302
having the fuse area 302b into a first portion (the left portion
beside the opening 310) and a second portion (the right portion
beside the opening 310) electrically insulated from the first
portion.
[0031] After a portion of the fuse area 302b is removed by the
light beam, the respective lens overlying the fuse area 302b may be
partially or completely removed. Referring to FIG. 3A, the lens
over the fuse area 302b is completely removed after the light beam
is irradiated and only the lens 306a and 306c not irradiated by the
light beam, remain on the fuse areas 302a and 302c, respectively.
Referring to FIG. 3B, in another embodiment, the lens 306b'
overlying the fuse area 302b is at least partially broken after
irradiation of the light beam. Whether the lens irradiated by the
light beam is partially broken or completely broken (completely
removed) may depend on the material of the lens and the energy of
the light beam.
[0032] Although the lens of the electronic device with a fuse
structure described above will be partially or completely removed
(or broken) after irradiated by the light beam, the embodiment of
the invention is not limited to a specific example. In another
embodiment, the lens overlying a fuse area which is at least
partially removed (or opened) by a light beam is completely
remained.
[0033] FIGS. 4A and 4B show a cross-sectional view and a top view
of an electronic device with a fuse structure according to an
embodiment of the present invention. In this embodiment, a
plurality of conducting layers 402 are formed between an optionally
formed passivation layer 404 and a substrate 400. A plurality of
lenses 406 including lenses 406a, 406b, and 406c are disposed on
the substrate 400. Each of the conducting layers 402 has a fuse
area ready for removal by a light beam if needed, wherein each of
the lenses is substantially aligned with a respective fuse area and
there is no optical device disposed between each of the lenses and
the respective fuse area.
[0034] Referring to FIGS. 4A and 4B, three fuse areas 402a, 402b,
and 402c are shown, and it is determined that the fuse area 402b of
the conducting layer 402 is to be at least partially removed by a
light beam to modify and/or repair the circuit of the electronic
device. A light beam, such as a laser light beam or other light
beam with enough energy and suitable wavelength, is directed to
irradiate the lens 406b. The light beam can be focused on a portion
of the fuse area 402b and an opening 410 is therefore formed in the
conducting layer 402 having the fuse area 402b. The opening 410
separates the respective conducting layer 402 into two electrically
insulated portions, and thus the circuit of the electronic device
is modified and/or repaired. In this case, the lens 402b is not
damaged by the light beam. Thus, the lens 402b is still on the
substrate 400.
[0035] Although each of the electronic devices of the embodiments
discussed above has a passivation layer formed between the fuse
area of the conducting layer and the lens, the embodiment of the
invention is not limited to specific examples. FIG. 5 shows a
cross-sectional view of an electronic device with a fuse structure
according to an embodiment of the present invention. In this
embodiment, a plurality of conducting layers 502 each having a fuse
area are formed in a substrate 500. A plurality of lenses 506 are
disposed on the substrate 500. Each of the lenses 506 is disposed
on one of the conducting layers 502. In this case, the lens 506
directly contacts with the fuse area of the conducting layer. No
passivation layer is formed therebetween. A light beam can also be
focused by the lens 506 onto the fuse area thereunder to open the
conducting layer and modify and/or repair the circuit of the
electronic device.
[0036] By disposing a lens between a fuse area of an electronic
device and a light beam, repair or modification of a circuit of the
electronic device may be efficiently performed. Additionally, the
chip size and fuse layout pitch (pitch between nearby fuse areas)
of an electronic device thereof may be reduced. In addition, the
cost of special machinery for producing the laser beam may also be
reduced.
[0037] While the invention has been described by way of example and
in terms of the preferred embodiments, it is to be understood that
the invention is not limited to the disclosed embodiments. To the
contrary, it is intended to cover various modifications and similar
arrangements (as would be apparent to those skilled in the art).
Therefore, the scope of the appended claims should be accorded the
broadest interpretation so as to encompass all such modifications
and similar arrangements.
* * * * *